Formulation of category-2 hypoglycemic Improved Traditional Medicines from selected Cameroonian medicinal plants: <i>Mangifera indica, Persea americana</i> and <i>Ageratum conyzoides</i>

Abstract

Diabetes mellitus is the fourth leading cause of death worldwide, and constitutes a major public health crisis. Management of the adverse condition relies mostly on synthetic drugs such as metformin, glibenclamide and insulin. However, treatment with synthetic drugs is challenged by side effects and high cost especially to patients in low-income countries like Cameroon. This study set out to formulate Improved Traditional Medicines (ITMs) in the form of capsules from lyophilized aqueous leaf extracts of Ageratum conyzoides, Mangifera indica and Persea americana, in combination, coded as ITM-1, and leaf extract of Mangifera indica alone, referred to as ITM-2. Phytochemical profiling of individual extracts was carried out using standard methods, while their antioxidant activity was evaluated in vitro by the 2,2-diphenyl-1-picryhadrazyl reducing (DPPH) assay and the Ferric (Iron) reducing antioxidant power assay (FRAP). Capsule formulation was guided by findings from prior Physicochemical and pharmacotechnical analysis of individual extracts and their combination. Safety studies were carried out both in vitro (cytotoxicity testing in Vero cells); and in vivo (acute toxicity tests using the mouse model). Preliminary evaluation of the antidiabetic potential of the formulated ITMs was achieved through determination of their acute hypoglycemic and antihyperglycemic properties in Wistar rats (Oral Glucose Tolerance Test). Major classes of phytochemicals detected were alkaloids, phenols, tannins, flavonoids, anthocyanins, tri-terpenes and anthraquinones. The DPPH and FRAP assays showed dose-dependent antioxidant activity for ITM-1 and ITM-2. Both ITMs showed no toxic effects, be it in vitro, (Cytotoxic Concentration 50% - CC50>1000 µg/mL in cells) or in vivo. At the dose of 25 mg/Kg, both ITMs exhibited significant hypoglycemic effects in Wistar rats. The ITM-2 capsules completely suppressed post-prandial glucose peak in rats as compared to the negative control (distilled water), ITM-1 capsule was able to cause restoration of the glucose levels to normal levels after 120 minutes